A. Field of the Invention
The present invention relates to application of a biologically active or chemical substance to relatively large volumes of target product, one example being pre-harvested or harvested crop, and in particular, to an apparatus, method, and system of applying biologically active or chemical substance in a minute ratio to the target product, whether it is moving relative to the substance, the substance is moving relative to it, or both.
B. Problems in the Art
It is many times desirable to treat harvested agricultural crop by applying substance having, at least in part, some biologically active organisms. One primary example is a forage inoculant which contains bacteria that, when applied in appropriate concentration to harvested agricultural crop, can reduce rate of degradation of the harvested agricultural crop.
In the example of forage inoculant, a relatively small concentration of inoculant can effectively treat a relatively large volume of harvested crop. For example, ratios on the order of 40 grams of inoculant to 50 tons of harvested crop are typical. However, relatively effective even application of such small quantities to such large quantities of agricultural crop is not a trivial matter, particularly if the crop or the applicator, or both, are moving relative to one another.
Additives are in common use for purposes of aiding in the preservation of the crop during storage. Two types of additives are the most common: (1) acid to reduce bacterial activity and, (2) inoculants to add favorable activity. These additives must be applied at time of harvest to provide the maximum benefit in the aid to preservation of the crop. Harvesting of the crop takes place over a large area through the use of mobile harvesting equipment such as forage harvesting and baling implements. These implements have been designed for maximum speed in harvesting with very little consideration of being compatible with the requirements of applying the additives used to aid in the preservation of the crop. The carrying capacity of harvesting equipment for additives being used is sometimes limited to small amounts of material. In such cases, it is beneficial to use additives that require the lowest ratio of additive to crop so, with limited carrying capacity, the harvesting implement is not stopping to refill small reservoirs for the additives on a frequent basis.
Additives to aid in the preservation of crops have been developed with increasing lower ratios of application in recent years. High-strength acid formulas have been introduced that are effective in controlling bacterial growth when applied at ratios a low as 0.005% of the crop being treated. Highly concentrated inoculants have been developed that are effective at rates as low as 0.001% of the crop being treated. These low inclusion rate products have reduced the need to stop and fill the reservoirs on the harvesting implements.
The problem that arises with the products that have low rates of application is attaining even coverage over the complete crop being treated. To be effective on the entire crop, coverage of these additives must be even on the entire crop. For liquids, conventional spray techniques are less than effective at these low rates.
One current method of inoculant application premixes concentrated inoculant with water in a large tank (e.g. 1:200 to 1:3000 ratio inoculant to water). Such tanks can hold, sometimes, on the order of 100 or more gallons of water. A conventional spraying system is then used to spray the mixture on the harvested crop. It is cumbersome and time consuming to mix, carry, and replenish such a large volume. It can also be wasteful of inoculant, which is biologically active and not inexpensive. Careful pre-mixing must take place. Sufficient power and fuel must be used to manipulate a tank of such size and weight. If the full tank of mixture is not used, the remainder most times must be thrown away. There is no practical way to store the mixture. Additionally, a relatively accurate spraying system must be used. The whole system usually must be taken back to a base location to refill and remix the tank. Such a spraying system uses a substantial amount of water per unit forage.
An alternative method was developed to address some of the aforementioned problems and deficiencies. The APPLI-PRO™ system available from Pioneer Hi-Bred International, Des Moines, Iowa, and disclosed at U.S. Ser. No. 10/140,596 and WO 99/58253, instead uses a palm or hand-sized APPLI-PRO™ container or bottle (see U.S. Pat. No. D409,303) of concentrated inoculant pre-mix that could be removably installed to its spraying system. A larger water tank is in fluid communication with a first pump, which pumps water from the tank at a desired rate to spray nozzles. A second pump, preferably an injection pump, is in fluid communication with the small inoculant concentration bottle and the fluid conduit. Precise, adjustable operation of the injection pump served as a precise metering of concentrated inoculant into the main water stream to the sprayers. This eliminated the requirement of pre-mixing in the large water tank. It allowed for dispensing of only the needed amount of inoculant. At the end of a spraying session, the inoculant bottle could either be exchanged or any remainder sealed and stored in that container, and then available for subsequent use. The system provides accurate, efficient utilization of inoculant with reduced margin of error. It is also highly adjustable for different needs. However, it requires two separate pumping mechanisms. Additionally, it still uses a substantially large holding tank for the water supply if large quantities of agricultural crop were to be sprayed in one session.
Other attempts have been made at improved forage inoculant-type application systems. In the ULV™ model, available from Pioneer Hi-Bred International, instead of a large water tank, either as a pre-mix tank or water supply tank, again a much smaller single container (e.g. 2.5 liters) contains the pre-mix of inoculant and water. Also, instead of spraying a ratio of a very small amount of inoculant to large amounts of water an atomizer is used to atomize the mixture in a very accurate, consistent manner to apply the right amount on the harvested forage. However, it has been found that an effective atomizer is relatively expensive, and that the overall apparatus can cost several thousands of dollars.
Therefore, additional room for improvement in the art still exists. A more economical, less cumbersome, efficient and effective application system is needed. Other factors must be considered in designing systems to apply such types of substances.
First, many biologically active substances have some threshold of tolerance for trauma. For example, some pumps and nozzles that try to atomize fluid many times subject the living cells to shearing forces that can damage their cells. Of course, damaged inoculant cells can inhibit or destroy their efficacy.
Secondly, care must be taken to avoid over-drying the biologically active substance, either while stored, awaiting application, or during application. Excessive drying or exposure to air can also reduce the efficacy of the biological ingredient.
Third, even with the specific example of forage inoculants, there are a wide variety of environments in which the inoculant could be applied and environmental factors could affect application. For example, it could be applied on a harvested crop moving past a spray device on some sort of an exposed conveyor. Care must be taken to direct the inoculant in an even manner on the moving crop. Conveyance equipment is becoming more and more sophisticated. The crop can be moving at substantial speeds and volumes. An inoculant application system must be able to be adjusted and adapted accordingly. For example, the application system might be carried on-board a harvesting device. Inoculant application may be made at or near the internal conveying systems, e.g. mechanical or pneumatic, of the machine. The speed the crop moves can be high; for example, over a hundred miles an hour. With exposed conveyors or internal conveyors, the effect of wind or vacuum on an airborne mixture created by high-speed venturi effect must be handled.
On the other hand, as detailed in Ser. No. 10/140,596 and WO 99/58253, there are other instances where the application system may be moving relative to the harvested crop, or both the sprayer and the crop moving. An effective application system must be able to handle those environments.
For purposes of this description, the term “target product” will be used to refer to any material, living or not, or any surface to which the apparatus, system or method of the present invention could be used to apply a biologically active or chemical substance in a liquid pre-mix form. For purposes of this description, the term “crop” will be used to refer to an example of a target product, and includes any plant material, whether pre-harvested (e.g. growing in a field or cut but without the desired part being yet harvested), or during and after harvesting.